1. Field of the Invention
The present invention relates to a signal processor which is built into a controller or the like for receiving a variety of signals, executing arithmetic and other operations on knowledge data in accordance with said signals and outputting control signals based on said knowledge data and more particularly to a novel bus connecting arrangement permitting direct access from a superior CPU to an internal knowledge data memory within the processor.
2. Description of the Prior Art
The commanding unit, such as a microprocessor or fuzzy processor, of various controllers has its own memory for storing knowledge data to be used in arithmetic or other operations. However, the interface for such memory is exclusively available to the microprocessor or fuzzy processor, and for access from a superior CPU to this knowledge data memory, a timing circuit for external access (hereinafter referred to as the arbiter circuit) is additionally required. Access from such a CPU to a control circuitry within the processor also requires an arbiter circuit. In such an arrangement, the status of operation of the processor is constantly monitored and switchovers are made using a plurality of arbiters.
However, the above prior art arrangement requires at least two arbiter circuits for access from the superior CPU to the processor and to its associated knowledge data memory, with the result that the whole circuit configuration is complicated. Moreover, installation of such arbiters not only increases the bulk of the device but adds to the initial cost of the device.
Furthermore, to provide for cases in which a plurality of demands compete for the knowledge data stored in said memory, it is common practice to load the memory with a software for setting an order of priority of such demands but if a bug exists in the software, the software will be a source of operational error. Therefore, this risk must be taken into consideration as a design factor.
Incorporation of such a software adds complexity to system architecture and calls for additional development time.
The present invention obviates the above-mentioned disadvantages. Thus, it is an object of the invention to provide a signal processor which is simple in circuit configuration and space-saving, contributory to cost reduction and, because of signal processing by hardware, insures high signal transmission accuracy and ease in system architecture.
Other objects and advantages of the invention will become apparent from the following description and accompanying drawings.